Field of the Invention
Leucocytes are body cells present in blood fluids which are part of the defense mechanism of mammalian systems. By mechanisms which are not entirely understood, leucocytes are attracted to foreign bacteria towards which they migrate and which, by certain means not relevant to the present invention, they ultimately destroy.
The rate at which the leucocytes migrate is related to the viability of the defense mechanism of any given mammalian system. It is known that in certain diseases this migratory activity is either impaired or abnormal. Among the diseases may be mentioned diabetes mellitus and periodontosis.
In vitro methods of measurement of leucocyte migratory activity are well known. One of these methods are set forth in some detail in J. Periodont Res. 14, 289-296 (1979). Briefly summarized, these methods involve the finding that certain substances, typically proteins or peptides have the ability to simulate the bacterial attraction and cause directed migration of the leucocytes. Such agents are known as chemotactic agents.
In the in vitro method, a sample of the patient's blood is taken. The sample is then reacted by methods well known in the art to remove first the red blood cells and thereafter to isolate the appropriate leucocytes. A test bed comprising, suitably, a Petrie dish filled with a suitable gel and having wells cut therein is then prepared. The chemotactic agent at a predetermined level of dilution is put into certain of these wells and the leucocytes from the test subject also diluted to a predetermined level are put into wells adjacent to those wells containing the chemotactic agent. The test medium is then incubated and after a predetermined time, the distance moved through the medium towards the chemotactic agent by the leucocytes is measured.
It will be understood that this procedure is extremely time consuming and it would be highly desirable to obtain the information yielded by these experiments in a more rapid manner.